/*
 * Event loop - empty template (basic structure, but no OS specific operations)
 * Copyright (c) 2002-2005, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "eloop.h"


struct eloop_sock {
        int sock;
        void *eloop_data;
        void *user_data;
        void (*handler)(int sock, void *eloop_ctx, void *sock_ctx);
};

struct eloop_timeout {
        struct os_time time;
        void *eloop_data;
        void *user_data;
        void (*handler)(void *eloop_ctx, void *sock_ctx);
        struct eloop_timeout *next;
};

struct eloop_signal {
        int sig;
        void *user_data;
        void (*handler)(int sig, void *eloop_ctx, void *signal_ctx);
        int signaled;
};

struct eloop_data {
        void *user_data;

        int max_sock, reader_count;
        struct eloop_sock *readers;

        struct eloop_timeout *timeout;

        int signal_count;
        struct eloop_signal *signals;
        int signaled;
        int pending_terminate;

        int terminate;
        int reader_table_changed;
};

static struct eloop_data eloop;


int eloop_init(void *user_data)
{
        memset(&eloop, 0, sizeof(eloop));
        eloop.user_data = user_data;
        return 0;
}


int eloop_register_read_sock(int sock,
                             void (*handler)(int sock, void *eloop_ctx,
                                             void *sock_ctx),
                             void *eloop_data, void *user_data)
{
        struct eloop_sock *tmp;

        tmp = (struct eloop_sock *)
                realloc(eloop.readers,
                        (eloop.reader_count + 1) * sizeof(struct eloop_sock));
        if (tmp == NULL)
                return -1;

        tmp[eloop.reader_count].sock = sock;
        tmp[eloop.reader_count].eloop_data = eloop_data;
        tmp[eloop.reader_count].user_data = user_data;
        tmp[eloop.reader_count].handler = handler;
        eloop.reader_count++;
        eloop.readers = tmp;
        if (sock > eloop.max_sock)
                eloop.max_sock = sock;
        eloop.reader_table_changed = 1;

        return 0;
}


void eloop_unregister_read_sock(int sock)
{
        int i;

        if (eloop.readers == NULL || eloop.reader_count == 0)
                return;

        for (i = 0; i < eloop.reader_count; i++) {
                if (eloop.readers[i].sock == sock)
                        break;
        }
        if (i == eloop.reader_count)
                return;
        if (i != eloop.reader_count - 1) {
                memmove(&eloop.readers[i], &eloop.readers[i + 1],
                        (eloop.reader_count - i - 1) *
                        sizeof(struct eloop_sock));
        }
        eloop.reader_count--;
        eloop.reader_table_changed = 1;
}


int eloop_register_timeout(unsigned int secs, unsigned int usecs,
                           void (*handler)(void *eloop_ctx, void *timeout_ctx),
                           void *eloop_data, void *user_data)
{
        struct eloop_timeout *timeout, *tmp, *prev;

        timeout = (struct eloop_timeout *) malloc(sizeof(*timeout));
        if (timeout == NULL)
                return -1;
        os_get_time(&timeout->time);
        timeout->time.sec += secs;
        timeout->time.usec += usecs;
        while (timeout->time.usec >= 1000000) {
                timeout->time.sec++;
                timeout->time.usec -= 1000000;
        }
        timeout->eloop_data = eloop_data;
        timeout->user_data = user_data;
        timeout->handler = handler;
        timeout->next = NULL;

        if (eloop.timeout == NULL) {
                eloop.timeout = timeout;
                return 0;
        }

        prev = NULL;
        tmp = eloop.timeout;
        while (tmp != NULL) {
                if (os_time_before(&timeout->time, &tmp->time))
                        break;
                prev = tmp;
                tmp = tmp->next;
        }

        if (prev == NULL) {
                timeout->next = eloop.timeout;
                eloop.timeout = timeout;
        } else {
                timeout->next = prev->next;
                prev->next = timeout;
        }

        return 0;
}


int eloop_cancel_timeout(void (*handler)(void *eloop_ctx, void *sock_ctx),
                         void *eloop_data, void *user_data)
{
        struct eloop_timeout *timeout, *prev, *next;
        int removed = 0;

        prev = NULL;
        timeout = eloop.timeout;
        while (timeout != NULL) {
                next = timeout->next;

                if (timeout->handler == handler &&
                    (timeout->eloop_data == eloop_data ||
                     eloop_data == ELOOP_ALL_CTX) &&
                    (timeout->user_data == user_data ||
                     user_data == ELOOP_ALL_CTX)) {
                        if (prev == NULL)
                                eloop.timeout = next;
                        else
                                prev->next = next;
                        free(timeout);
                        removed++;
                } else
                        prev = timeout;

                timeout = next;
        }

        return removed;
}


int eloop_is_timeout_registered(void (*handler)(void *eloop_ctx,
                                                void *timeout_ctx),
                                void *eloop_data, void *user_data)
{
        struct eloop_timeout *tmp;

        tmp = eloop.timeout;
        while (tmp != NULL) {
                if (tmp->handler == handler &&
                    tmp->eloop_data == eloop_data &&
                    tmp->user_data == user_data)
                        return 1;

                tmp = tmp->next;
        }

        return 0;
}


/* TODO: replace with suitable signal handler */
#if 0
static void eloop_handle_signal(int sig)
{
        int i;

        eloop.signaled++;
        for (i = 0; i < eloop.signal_count; i++) {
                if (eloop.signals[i].sig == sig) {
                        eloop.signals[i].signaled++;
                        break;
                }
        }
}
#endif


static void eloop_process_pending_signals(void)
{
        int i;

        if (eloop.signaled == 0)
                return;
        eloop.signaled = 0;

        if (eloop.pending_terminate) {
                eloop.pending_terminate = 0;
        }

        for (i = 0; i < eloop.signal_count; i++) {
                if (eloop.signals[i].signaled) {
                        eloop.signals[i].signaled = 0;
                        eloop.signals[i].handler(eloop.signals[i].sig,
                                                 eloop.user_data,
                                                 eloop.signals[i].user_data);
                }
        }
}


int eloop_register_signal(int sig,
                          void (*handler)(int sig, void *eloop_ctx,
                                          void *signal_ctx),
                          void *user_data)
{
        struct eloop_signal *tmp;

        tmp = (struct eloop_signal *)
                realloc(eloop.signals,
                        (eloop.signal_count + 1) *
                        sizeof(struct eloop_signal));
        if (tmp == NULL)
                return -1;

        tmp[eloop.signal_count].sig = sig;
        tmp[eloop.signal_count].user_data = user_data;
        tmp[eloop.signal_count].handler = handler;
        tmp[eloop.signal_count].signaled = 0;
        eloop.signal_count++;
        eloop.signals = tmp;

        /* TODO: register signal handler */

        return 0;
}


int eloop_register_signal_terminate(void (*handler)(int sig, void *eloop_ctx,
                                                    void *signal_ctx),
                                    void *user_data)
{
#if 0
        /* TODO: for example */
        int ret = eloop_register_signal(SIGINT, handler, user_data);
        if (ret == 0)
                ret = eloop_register_signal(SIGTERM, handler, user_data);
        return ret;
#endif
        return 0;
}


int eloop_register_signal_reconfig(void (*handler)(int sig, void *eloop_ctx,
                                                   void *signal_ctx),
                                   void *user_data)
{
#if 0
        /* TODO: for example */
        return eloop_register_signal(SIGHUP, handler, user_data);
#endif
        return 0;
}


void eloop_run(void)
{
        int i;
        struct os_time tv, now;

        while (!eloop.terminate &&
                (eloop.timeout || eloop.reader_count > 0)) {
                if (eloop.timeout) {
                        os_get_time(&now);
                        if (os_time_before(&now, &eloop.timeout->time))
                                os_time_sub(&eloop.timeout->time, &now, &tv);
                        else
                                tv.sec = tv.usec = 0;
                }

                /*
                 * TODO: wait for any event (read socket ready, timeout (tv),
                 * signal
                 */
                os_sleep(1, 0); /* just a dummy wait for testing */

                eloop_process_pending_signals();

                /* check if some registered timeouts have occurred */
                if (eloop.timeout) {
                        struct eloop_timeout *tmp;

                        os_get_time(&now);
                        if (!os_time_before(&now, &eloop.timeout->time)) {
                                tmp = eloop.timeout;
                                eloop.timeout = eloop.timeout->next;
                                tmp->handler(tmp->eloop_data,
                                             tmp->user_data);
                                free(tmp);
                        }

                }

                eloop.reader_table_changed = 0;
                for (i = 0; i < eloop.reader_count; i++) {
                        /*
                         * TODO: call each handler that has pending data to
                         * read
                         */
                        if (0 /* TODO: eloop.readers[i].sock ready */) {
                                eloop.readers[i].handler(
                                        eloop.readers[i].sock,
                                        eloop.readers[i].eloop_data,
                                        eloop.readers[i].user_data);
                                if (eloop.reader_table_changed)
                                        break;
                        }
                }
        }
}


void eloop_terminate(void)
{
        eloop.terminate = 1;
}


void eloop_destroy(void)
{
        struct eloop_timeout *timeout, *prev;

        timeout = eloop.timeout;
        while (timeout != NULL) {
                prev = timeout;
                timeout = timeout->next;
                free(prev);
        }
        free(eloop.readers);
        free(eloop.signals);
}


int eloop_terminated(void)
{
        return eloop.terminate;
}


void eloop_wait_for_read_sock(int sock)
{
        /*
         * TODO: wait for the file descriptor to have something available for
         * reading
         */
}


void * eloop_get_user_data(void)
{
        return eloop.user_data;
}
